Inflammatory plasma transfer induces early ovarian CD8+ accumulation without overt pathology

Abstract

Autoimmune-associated reproductive dysfunction is frequently linked to ovarian immune infiltration and circulating ovarian autoantibodies, yet it remains unclear whether circulating factors alone can initiate immune changes in the ovary before overt histopathology is detectable. In prior work using interferon-γ (IFN-γ) AU-rich element deletion (ARE) mice, chronic inflammation was associated with increased ovarian CD8⁺ T cell infiltration and reproductive dysfunction. Here, we tested whether circulating factors from ARE mice are sufficient to induce early ovarian immune remodeling in healthy hosts. Pooled plasma from WT, ARE^+/-, or ARE^-/- female donors was administered intraperitoneally to age-matched WT female recipients, and tissues were harvested on day 8. Ovaries were assessed by H&E histopathology and CD8 immunohistochemistry; spleen and draining lymph nodes (dLNs) were analyzed by flow cytometry. In parallel, circulating anti-ovarian antibody levels were quantified in donors, and genotype-dependent ovarian tissue binding was evaluated by incubating Rag1^-/- ovarian sections with donor plasma followed by immunofluorescent detection and whole slide image quantification. Passive plasma transfer did not induce overt ovarian histopathology by H&E at day 8. However, CD8 immunohistochemistry revealed a genotype-dependent increase in ovarian CD8⁺ cell accumulation, highest in ARE^-/- plasma recipients. Moreover, flow cytometry showed increased CD8⁺ T cell frequencies in dLNs in ARE^-/- plasma recipients. Donor ARE^-/- mice exhibited elevated circulating ovarian autoreactivity and their plasma showed increased binding to Rag1^-/- ovarian tissue ex vivo. Together, these data indicate that short-term exposure to disease-associated plasma can initiate an ovarian immune shift.